1. Field of the Invention
The present invention relates to a video server, a video editing system with a variable speed preview function, and a method for recording and reproducing video data of the video server.
2. Description of the Related Art
Generally, in a program transmission system of television broadcasting, a recording video such as a video transmitted via a line and a video by a monitor camera are stored in a video server once. The video stored in the video server is edited by an operator and then appropriately transmitted from the video server. The operator edits the video stored in the video server while reproducing the video on a preview monitor.
In previewing for editing, it is preferable for the program transmission system in terms of efficiency to reproduce a video at an equal speed or a low speed in a section of a large variation of the video and to reproduce the video at a high-speed such as a double speed reproduction in a section of a small variation of the video. Especially, recording video to be transmitted from relay broadcasting site via the line is a monotonous video having a small variation or rarely having a variation in many cases, it is preferable to reproduce at a high speed in the section of such a monotonous video. Therefore, conventionally, a method, for manually searching points at which the video the video has changed through a shuttle operation, performs high-speed reproduction in the section of the monotonous video on the basis of the search, and performs an equal-speed reproduction and a low-speed reproduction, is employed.
In contrast, a video system, in which records a video on a recording medium by imaging the video at a frame rate of a slightly higher speed or a slightly lower speed than a standard frame rate by means of an imaging unit of which the frame rate in imaging is variable and by reproducing the video at the standard frame rate in reproducing, obtains a vigorous slow motion video and a vigorous high speed motion video, has been well known.
Jpn. Pat. Appln. KOKAI Publication No. 2002-320203 discloses a technique for automatically adjusting a reproduction speed in accordance with rate information in the case in which such a video system records information directly of indirectly indicating the frame rate at the imaging unit together the video on the recording medium and reproduces the video at a frame different from the standard frame rate in reproducing.
Jpn. Pat, Appln. KOKAI Publication No. 2004-180289 discloses a technique which records information showing a frame rate in imaging together with a video signal in a system similar to the technique disclosed in Jpn. Pat. Appln. KOAKI Publication No. 2002-320203, distinguishes the frame rate in imaging at editing, and adjusts a frame rate in reproducing.
However, Jpn. Pat. Appln. KOKAI Publication No. 2002-320203 and Jpn. Pat. Appln. KOKAI Publication No. 2004-180289 do not describe the techniques for automatically adjusts the frame rates in reproducing in response to changes in video.
As mentioned above, in editing the video stored in the video server while reproducing the video on a preview monitor, it is preferable to reproduce the video at a relative slow speed in a section with a drastic change in video and to reproduce at a high speed in a section with a small change. In this case, generally, since a method of the video system for manually searching points at which changes in video have occurred by the shuttle operation and for manually adjusting a reproduction speed on the basis of the search result, there is a problem that work efficiency of editing by an operator is poor.